I bought my 996tt back in December..Great car and was lowered on H&R springs. Every since I got it I've had a shake in my steering wheel at higher speeds over 70mph. I've aligned it, changed it to gt2 suspension, etc...

Car goes straight, rides fine but has a slght looseness to at higher speeds. If I'm going fast the car goes straight but the wheel will go back and forth a little following the bumps in the road. I'm not sure if its just the nature of he porsche 996tt (silly if you ask me) or if its some worn bushings in the front end.

Myself and my alignment guy both agreed that most of the bushings that we could find were in excellent shape.

I talked to a big Porsche guy down in FL named Eddie Bello as he just did a clutch on my car the other day. He mentioned it might be the thrust arm, I'm thinking the side on the inside maybe?

I've found the adjustable thrust bushing for the lower control arm but what about the inner side that is closer to the center of the car? Any ideas?

 

Ensure the wheels are balanced. I've had to have mine re-balanced after they were balanced by the Porsche dealer. Also check that the tires are not out of round.

 

Mine was doing that with the humps in the road, and when I got home from picking up the car in Houston, the air pressure in all the tires were really low. Put them at factory spec and it doesn't do it anymore...

 

It's Eddie from Kendall/Miami?
Have you check the inner/outer tie-rods on the steering rack?
joel

 

This sounds to me like a tire issue. Do you know anyone else with a TT that you could swap wheels with just to check? Sometimes the belts in the tires get loose.

 

I had the same issue. Had put new PS2's/rims on the car. Had it balanced/aligned by a very reputable P-guy. Turned out to be a front rim out of true. Had it repaired & the car tracks true.

 

It did it with the stock wheels, and it does it with the iforged wheels since day one. A porsche mechanic told me today it may need more toe out in the front? It has .05 on both sides for a total of .10 toe in the front. He also told me that it the 996tt naturally wanders at high speeds a little if you let go of the wheel, it goes straight but the steering wheels wiggles back and forth. I'm confused.

 

My 03 didn't wiggle any at all on recent road trip and at somewhat sustained elevated speeds under very hot ambient temperature conditions.

My car has new 18" Contis and car aligned -- stock springs/suspension -- just a few days before I left and I'm sure tire pressures ok all around.

What tires are you running? N-series and quality or some other kind? Have you double checked tire inflation pressures cold with a quality tire gage?

My experience with a couple of various Porsche models is tire inflation pressure critical to good tire and car performance, handling, steering feel.

Sincerely,

Macster.

 

35psi up front on toyo proxes (newest with AA grip and 280 war rating) and 37 psi in the rear.

 

I work on porsche's professionally myself in california, and I was just thinking that your wheels themseleves might be out of round and if that is not the case then the steering rack itself may be the cause of the issue. Especailly if the tires are balanced and not flat spotted with a solid front end that is tight in all of the known suspension bolt on points.

 

Oh, and I would highly recommend to stick with the factory 37psi in the front and 44psi in the rear due to being the best for that car and a factory spec!

 

Any particular way to tell if the steering rack goes bad?

 

mostly just the feeling in the way it goes lock to lock, so it might feel a little notchy. Another thing is that there is a bushing in the steering rack that gets worn out over time but not likely, The wheels and tires are the biggest and most common forms of steering shimmy's. Another little thing to look at would be the matching of the front bumper of the rear spoiler if they are modified.

 

stock bumpers just painted to match. Steering is smooth but going fast up top is the little loosness. Bushing going bad huh? Should I bring it to porsche, independant shop, or live with it since it might be normal, lol.

 

Is your car lowered? It could be you are experiencing bump steer. Ask the experts about it. But I would check out the other things first.